Just put the book down and enjoyed the hell out of it.
My favorite aspects were the descriptions of the Crusaders' apparel and hometown. Shiny and satiny cloth, flying cars with smooth lines, and archaic mixed with far-flung future -- they all put me into a 60s Trek frame of mind. I could even imagine the green glow of the gravity weapons being depicted in 60s TV special effects. Nicely done by the author to capture the aesthetic of TOS so well.
Another high mark in the book was the chapter that detailed the pursuit and evasion of Kirk, Spock and the High Priestess (who I pictured as the super-tall actress from Game of Thrones) in the flying cars through the city. A fun roller coaster ride of a narrative -- reminded me of my visit last year to Disney World and the Star Wars ride. Again a nice bit of writing.
Just an off-hand question: Does the name Elena Collins come from anything vampire-related? Just wondering.